Study of Sorption Capacity and Surface Morphology of Carbon Nanomaterials/Chitosan Based Aerogels

In this research aerogels were synthesized by homogenization of carbon nanotubes and chitosan under ultrasonic treatment and active magnetic stirring, followed by freeze-drying in order to remove the liquid from its structure. Freeze-drying is characterized by a certain ratio of pressure and temperature at which the solid phase, in our case – the ice, turns into a gas without passing through a liquid phase. Freezedrying was carried out at a temperature of –15 °C and a pressure of 30–40 Pa. After freeze-drying which lasted for 20 h, the as-obtained aerogels were carbonized at temperature of 800 °C in an inert atmosphere. Surface morphology of resulting aerogels was studied using scanning electron microscopy. The hydrophobicity and sorption capacity of these aerogels to organic liquids characterized by different densities were investigated. In addition, composite aerogels with the presence of graphene nano-platelets in the structure were obtained and the influence of introduction of graphene nanoplatelets on aerogel’s properties was analyzed. It was found that composite aerogels based on graphene and carbon nanotubes with chitosan as a glue matrix are characterized by a better-developed porosity of surface with a smaller pore sizes, and their sorption capacity for organic liquids is higher compared with the aerogels based on carbon nanotubes

Spongy Structures Coated with Carbon Nanomaterials for Efficient Oil/Water Separation

Rapid progress of processing and transportation of oil and petroleum products may cause disaster for environment like oil spill. Oil booms, combustion, and oil skimmer vessels are usually used to clean up the oil spill, but often with poor efficiency and even with undesirable environmental side effects. With obtaining of carbon nanomaterials (CNMs) (graphene, carbon nanotubes) and developing inexpensive technologies for their synthesis it has become perspective to use them for creation of 3D structures which may serve as a hydrophobic sorbents for oil and petroleumproducts. In this study, sponges coated with carbon nanomaterials were obtained using “dip-coating” method. Walls of commercially available polyurethane (PU) and melamine sponges were coated with reduced graphene oxide (rGO) and multiwalled carbon nanotubes (MWCNTs). The resulting sponges are characterized by excellent mechanical properties, they are superhydprophobic, and they fully repel water and at the same time selectively absorb oil and organic liquids of different densities. We believe that superhydrophobic and superoleophilic sponges, the walls of which are coated with CNMs, are perspective candidates for reusable sorbents for collection of oil and petroleum products from the surface of water and moreover due to its excellent mechanical properties they can serve as a hydrophobic filtering materials for separation of oil from the surface of water

Cognitive pedagogy and teaching approaches via e-learning system

The 21th century changed the way of learning from traditional campus-based learning to e-learning. It is obvious that the e-learning system has become functional due to the cur-rent global COVID 19 pandemic, which since March 2020 has actively begun to influ-ence the Kazakhstani education system. All education systems have switched from tra-ditional classroom teaching to distance learning, which to varying degrees imitates and uses the format of classroom studies. This article deals with learning and teaching ap-proaches on the basis of the e-learning education system and cognitive pedagogy in dig-ital era. There is also a description of research experiment results conduced on English First online platform at Satbayev University in Kazakhstan. The results were positive. In addition, authors highlight challenges of information communication technologies in ed-ucation and discuss different theories devoted to digital education